There is no longer any doubt that the system of cellular canceration is an oncogenic mechanism/process induced by abnormalities in signal transduction mechanisms. In recent years, a new concept has been proposed, in which sustention of a signal associated with the differentiation process of a specific cell lineage is involved in the oncogenic process by serving as a lineage-specific survival signal. The concept has drawn great attention as it contributes to the elucidation of tissue-specific oncogenic mechanism.
The present inventors reported for the first time in the world that while the thyroid transcription factor-1 (TTF-1) gene, which is involved in peripheral lung differentiation, contributes as a master regulatory factor of cell differentiation. Its persistent expression is essential for the survival of pulmonary adenocarcinoma, and it is closely involved in the development and progression of cancer (Non-patent Document 1).